Elastically stretchable composite sheet and process for making the same

ABSTRACT

An elastically stretchable composite sheet that includes an elastic layer and an inelastic layer formed with stretchable fibers having a relatively small diameter and bonded to at least one surface of the elastic layer. In the inelastic layer bonded to the elastic layer is formed with thermoplastic synthetic fiber, at least 80% by weight of stretchable fibers includes thermoplastic synthetic fiber containing lubricant of 0.1~5.0% by weight.

BACKGROUND OF THE INVENTION

This invention relates to an elastically stretchable composite sheetcomprising a stretchable elastic layer and a stretchable inelastic layerbonded to each other and a process for making the elasticallystretchable composite sheet.

PCT Japanese Patent Application Publication No. 1996-504693A describes amultilayered elastic sheet-like structure comprising a rubber-basedelastic layer and an inelastic fibrous layer. This sheet-like structureof prior art is obtained by a process comprising steps of placing theserubber-based elastic layer and inelastic fibrous layer upon each other,melting them together or bonded them to each other, stretching them by100˜200% and then relaxing them. The rubber-based elastic layer isformed with a film or the like and the inelastic fibrous layer is formedwith a web made from long fibers such as a spun bond or melt blown fiberweb.

According to the prior art as disclosed in the Publication, if it isintended to form the inelastic fibrous layer with, for example, longfibers of polypropylene, a stretch ratio of polypropylene in the step ofmelt spinning should be limited to a value as low as possible in orderthat these long fibers can be stretched together with the elastic layerby 100˜200%. This is because that a high stretch ratio of polypropylenewould promote crystallization of polypropylene which would, in turn,make it impossible to stretch this inelastic fibrous layer together withthe elastic layer at a desired high stretch ratio in the subsequentstep. The stretch ratio thus limited in the step of melt spinning willnecessarily make it impossible to use the fibers of a desired smalldiameter. With a disadvantageous consequence, the resultant fibers willgive a wearer of the sanitary article using such fibers a touch lessthan the article using the fibers of appropriately small diameter. Inaddition, if it is intended to obtain a multilayered elastic sheet-likestructure including a bulky inelastic fibrous layer, the fiber havingits diameter as small as possible may be used to improve its bulkinessand furthermore to reduce a material cost. However, such advantage canbe not obtained so far as the fiber diameter tends to be large.

SUMMARY OF THE INVENTION

It is an object of this invention to provide an elastically stretchablesheet-like structure comprising an elastic layer and an inelasticfibrous layer formed with fibers each having a relatively smalldiameter.

According to one aspect of this invention, there is provided anelastically stretchable composite sheet comprising an elastic layer, theelastic layer being elastically stretchable at least in one direction,and an inelastic layer of fibers, the inelastic layer beinginelastically stretchable in the one direction and bonded to at leastone surface of the elastic layer and, according to another aspect ofthis invention, there is provided a process for making such anelastically stretchable composite sheet.

The elastically stretchable composite sheet an the process for makingthe composite sheet further comprise at least 80% by weight of saidfibers including thermoplastic synthetic fiber containing lubricant of0.1˜5.0% by weight.

The elastically stretchable composite sheet according to this inventionuses the fibers containing the lubricant as the stretchable fibers whichcan be stretched at a ratio sufficiently higher than in the case of thefiber contains no lubricant to reduce the fiber-diameter and thereby toprovide the composite sheet with a desired comfortable touch. Thethermoplastic synthetic resin as raw material for the stretchable fiberhas a fluidity improved by addition of the lubricant and makes itpossible to set the nozzle temperature of the extruders at a relativelylow level. This facilitates, in turn, the fiber discharged from theextruders to be cooled. In this way, a cost for operation of theextruders is reduced and a productivity of the stretchable fibers isimproved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a composite sheet (first compositesheet);

FIG. 2 is a view similar to FIG. 1 depicting a composite sheet (secondcomposite sheet);

FIG. 3 is a view similar to FIG. 1 depicting a composite sheet (thirdcomposite sheet);

FIG. 4 is a diagram schematically illustrating a process for making thecomposite sheet; and

FIG. 5 is a diagram similar to FIG. 4 schematically illustrating aprocess arranged in different manner from that illustrated in FIG. 4 formaking the composite sheet.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Details of an elastic stretchable composite sheet and a process formaking the same according to this invention will be more fullyunderstood from the description given hereunder with reference to theaccompanying drawings.

FIGS. 1, 2 and 3 are perspective views of a first composite sheet 1A, asecond composite sheet 1B and a third composite sheet 1C, respectively,depicting the elastically stretchable composite sheet according to thisinvention in different states and embodiments. Both the first compositesheet 1A and the second composite sheet 1B respectively have an upperlayer 2 and a lower layer 3 integrally bonded with together in firstbond regions 4A. The upper layer 2 of the first composite sheet 1A isinelastically stretchable at least in a direction indicated by Y—Y oftwo directions indicated by X—X and Y—Y and the lower layer 3 iselastically stretchable at least in the Y—Y direction of the twodirections indicated by X—X and Y—Y.

The upper layer 2 is an assembly of continuous fibers 6 made ofthermoplastic synthetic resin in which the fibers are bonded togetherpreferably only in the first bond regions 4A but not in the remainingregion defined between each pair of the adjacent first bond regions 4A,4A. The continuous fibers 6 extend on the upper surface of the lowerlayer 3 to describe irregular curves.

Such continuous fibers 6 may be of thermoplastic synthetic resin such aspolyproplylene, polyester or polyethylene and 80% by weight of thesefibers 6 contains at least one type of lubricant such as fatty acidamide, fatty acid ester or metallic soap. More preferably, 80% by weightof these fibers 6 containing the lubricant are those of polypropylene'shomopolymer, ethylene/propylene copolymer, ethylene/propylene/butene ora fibrous mixture containing at least two of these fibers. Thecontinuous fibers 6 preferably contain the lubricant by 0.1˜5% by weightthereof and may contain inorganic filler such pigment or dye or bariumsulfate at most by 5% by weight thereof. 20% by weight or less of thesecontinuous fibers may comprise thermoplastic synthetic fibers, chemicalfibers or natural fibers containing no lubricant.

The respective lower layers 3 of the first and second composite sheets1A, 1B are sheets being elastically stretchable in the direction Y—Y,preferably in both the direction Y—Y and the direction X—X at least by100%, preferably by 200% and more preferably at least by 400%. Afterhaving been stretched by 100%, these sheets can contract to a length 1.3times or less with respect to their initial length. Such sheets may beformed by card web of elastic threads, nonwoven fabric of elasticthreads in the form of a thermal bond nonwoven fabric or a spun lacenonwoven fabric, a woven fabric of elastic threads, or a film ofstyrene- or olefine-based thermoplastic elastomer.

The first bond regions 4A should be intermittently arranged in thedirection Y—Y and otherwise not specified. However, it is preferred toarrange them intermittently also in the direction X—X and to dimensionan area of the individual bond region in a range of 0.1˜10 mm².

These upper layer 2 and a lower layer 3 may be bonded together in thefirst bond regions 4A either by heating them under pressure or bysubjecting them to a ultrasonic treatment. Alternatively, the continuousfibers 6 forming the upper layer 2 may be mechanically intertwined witha structure of the lower layer 3 to bond these two layers 2, 3 together.To achieve such intertwinement, various means such as needle punchingand high pressure columnar water stream ejection may be utilized. It isalso possible to bond these upper layer 2 and lower layer 3 together inthe first bond regions 4A with a suitable adhesive agent.

Of the first and second composites sheets 1A, 1B as have been describedabove, in the case of the first composite sheet 1A, the upper layer 2 isinelastically stretched at a given ratio and the lower layer 3 iselastically stretched at the given ratio, as the sheet 1A is stretchedat the given ratio in the direction Y—Y as indicated by chain lines.Relieved of the tension, the lower layer 3 can elastically contractsubstantially to its initial dimension. Thereupon, the upper layer 2having been stretched under a plastic deformation of the continuousfibers 6 is compelled by a contractile force of the lower layer 3 tocontract with formation of large loops or a plurality of gathers,although the upper layer 2 itself has no contractile force.

The second composite sheet 1B depicted in FIG. 2 corresponds to thefirst composite sheet 1A having been stretched once and then left tocontract in the manner as has been described above.

The third composite sheet 1C corresponds to the second composite sheet1B additionally provided with second bond regions 4B. Each of thesesecond bond regions 4B has an area smaller than the area that each ofthe first bond regions 4A has, but has its number per unit area largerthan the number per unit of the first bond regions 4A.

While both the first composite sheet 1A and the second composite sheet1B are elastically stretchable, there are differences between them. Oneof the differences lies in that a length of the continuous fibers 6extending in the direction Y—Y between each pair of the adjacent bondregions 4A, 4A in the first composite sheet 1A is different from thecorresponding length in the second composite sheet 1B. Specifically, thecontinuous fibers 6 in the second composite sheet 1B are longer andfiner than those in the first composite sheet 1A by the length and thefineness changed due to plastic deformation thereof. The continuousfibers 6 deformed in this manner form large loops and/or a plurality ofgathers between each pair of the adjacent first bond regions 4A, 4A asthe first composite sheet 1A once having been stretched contracts toform the second composite sheet 2B. The upper layer 2 of the secondcomposite sheet 1B having such loops and/or gathers is more bulky andflexible than the upper layer 2 in the first composite sheet 1A has,offering a wearer of the sanitary article using such composite sheet acomfortable touch. Another difference between the first and secondcomposite sheets 1A, 1B lies in a force required to stretch thesecomposite sheets 1A, 1B in the direction Y—Y. Specifically, the forcerequired to stretch the first composite sheet 1A at the desired ratiocomprises the force required for plastic deformation of the continuousfibers 6 of the upper layer 2 plus the force required for elasticdeformation of the lower layer 3. On the other hand, only the forcerequired to stretch the lower layer 3 is sufficient to stretch thesecond composite sheet 1B at the desired ratio. This is because that theupper layer 2 has its continuous fibers 6 already stretched sufficientlyto eliminate a demand for further stretch. The upper layer 2 merelychanges its direction as the second composite sheet 1B is stretched andsubstantially no affection on the force required to stretch the secondcomposite sheet 1B. The continuous fibers 6 describing the loops and/orthe gathers are straightened between the respective pairs of theadjacent first bond regions 4A, 4A in which the continuous fibers 6 arebonded to the lower layer 3 as the second composite sheet 1B with thelower layer 3 being elastically deformed. The force required to furtherstretch the second composite sheet 1B from such state comprises theforce required to stretch the lower layer 3 plus the force required tostretch the straightened continuous fibers 6.

FIG. 4 is a diagram schematically illustrating an example of the processfor making the first˜third composite sheets 1A˜1C. An endless belt 30travels from the left to the right as viewed in FIG. 4. In the vicinityof the left end, a first melt blown fiber extruder 31 is provided abovethe belt 30 and a suction mechanism 31A is provided below the belt 30.The first extruder 31 has a plurality of nozzles arranged transverselyof the belt 30 and discharges from these nozzles first melt blowncontinuous fibers 35 of inelastic thermoplastic synthetic resin. Thesecontinuous fibers 35 are stretched or not stretched before they areaccumulated on the belt 30 so as to describe irregular curves and toform a first web 41. A discharging condition of the first extruder 31 aswell as a travelling condition of the belt 30 are selected so that, inthe first web 41, the first continuous fibers 35 accumulated one uponanother on the belt 30 may be free from being fused together or, iffused together, these continuous fibers 41 may be easily separated onefrom another in the subsequent step. These first continuous fibers 35preferably have a breaking extension of 300% or higher. The firstcontinuous fibers 35 having such level of breaking extension is ofthermoplastic synthetic resin such as polypropylene, polyester orpolyethylene containing lubricant such as fatty acid amide, fatty acidester or metallic soap by 0.1˜5.0% by weight thereof. The polypropylenepreferably takes the form of homopolymer, or ethylene/propylenecopolymer or ethylene/propylene/butene copolymer containing thelubricant by 0.1˜5.0% by weight thereof.

On the right of the first extruder 31, there are provided a second meltblown fiber extruder 32 and a suction mechanism 32A. The second extruder32 also has a plurality of nozzles arranged transversely of the belt 30and discharges from these nozzles second melt blown continuous fibers 40of elastically stretchable thermoplastic elastomer and these continuousfibers 40 are accumulated on the belt 30 so as to describe irregularcurves and to form a second web 42. A discharging condition of thesecond extruder 32 is selected so that the second continuous fibers 40accumulated one upon another may be fused together and the second web 42may form a sheet which is elastically stretchable in the travellingdirection of the belt 30, more preferably not only this travellingdirection of the belt 30 but also in the direction orthogonal to thetravelling direction. The second continuous fibers 40 preferably have abreaking extension higher than that of the first continuous fibers 35.

The first and second webs 41, 42 placed upon each other are fusedtogether under heat and pressure in the first bond regions 4A arrangedintermittently in their longitudinal direction corresponding to thetravelling direction of these webs 41, 42 and in their transversedirection orthogonal to the longitudinal direction, at least in thelongitudinal direction to form a first composite web 43A correspondingto the first composite sheet 1A as these first and second webs 41, 42pass through a nip defined between a pair of embossing rolls 34, 34. Thefirst bond regions 4A are provided so that each of them has a size, forexample, of 0.1˜10 mm² and spaced apart from the longitudinally as wellas transversely adjacent first bond regions 4A by 3˜30 mm, respectively.

The first composite web 43A then passes through a nip defined betweenfirst and second drawing rolls 36, 37. A velocity at which the firstroll 36 rotates is lower than a velocity at which the second roll 37rotates and this differential velocity is selected so that the firstcomposite web 43A may be stretched at a desired ratio, for example, of50˜300% without exceeding a breaking extension of the first web 41 andthe maximum elasticity of the second web 42. The second web 42 iselastically stretched between the immediately precedent first bondregion 4A and the immediately following first bond region 4 a as viewedin the travelling direction. At the same time, the first continuousfibers 35 are straightened in the travelling direction between the pairof the first bond regions 4A, 4A and then plastically deformed to form asecond composite web 43B.

The second composite web 43B formed in this manner then proceeds to apair of third rolls 38. A velocity at which these third rolls 38 rotateis the same as that of the first rolls 36 so that the second compositeweb 43B elastically contracts to the length of the first composite web43A between the second rolls 37 and the third rolls 38. The third rolls38 function also as embossing rolls adapted to partially emboss thesecond composite web 43 having elastically contracted and thereby toform a third composite web 43C having the second bond regions 4B of FIG.3. The second bond regions 4B are provided so that each of them has asize, for example, of 0.1˜5 mm² and spaced apart from the longitudinallyas well as transversely adjacent second bond regions 4A by 0.5˜5 mm,respectively, longitudinally as well as transversely of the thirdcomposite web 43C. While the second bond regions 4B are preferablyspaced apart from the first bond regions 4A, exploitation of theinvention will not be affected even if some of the second bond regions4B are placed upon some of the first bond regions 4A.

Thereafter the first composite web 43A may be cut into an appropriatedimension to obtain the first composite sheet 1A of FIG. 1. The secondcomposite web 43B having contracted in the manner as has been describedabove may be cut into an appropriate dimension to obtain the secondcomposite sheet 1B of FIG. 2. Similarly, the third composite web 43C maybe cut into an appropriate dimension to obtain the third composite sheet1C of FIG. 3. The composite sheet obtained from the second composite web43B has only the first bond regions 4A and the composite sheet obtainedfrom the third composite web 43C has the first bond regions 4A and thesecond bond regions 4B. The first continuous fibers 35 used in theprocess illustrated by FIG. 4 correspond to the continuous fibers 6 inFIGS. 1˜3 and the first web 41 comprising these fibers 6 is destined toform the upper layer 2 of FIGS. 1˜3. The second web 42 is destined toform the lower layer 3 of FIGS. 1˜3. In this process, the third pair ofrolls 38 may be provided in the form of the rolls merely functioning asfeed rolls similar to the first pair of rolls 36.

In the second composite web 43B and the third composite web 43C obtainedin this manner, the first and second webs 41, 42 may be stretched afterthey have been bonded together in the first bond regions 4A to loosenfusion or entanglement among the fibers of the first web 41. Unevendistribution of the first continuous fibers 35 in the first web due tosuch fusion or intertwinement can be thereby eliminated to obtain thesecond and third composite webs 43B, 43C presenting a uniform touch.

In the process for making the first-third composite sheets 1A˜1Caccording to this invention, the first composite web 43A can bestretched also in its transverse direction orthogonal to the directionin which the first composite web 43A travels. Thereby the portion of thefirst continuous fibers 35 extending transversely of the first compositeweb 43A can be stretched. The second bond regions 4B of the thirdcomposite web 43C serve to firmly bond the first web 41 now free fromunevenness of their distribution to the second composite web 42 so thatthese two webs 41, 42 will not be separated from each other even ifstretch and contraction are repeated.

The first continuous fibers made from thermoplastic synthetic resin,particularly homopolymer of polypropylene or propylene copolymer used inthis process may be added with suitable lubricant to alleviate africtional resistance among the polymer molecules and a crystallizationpossibly occurring in the course of stretching. Consequently, the firstweb 41 formed with the first continuous fibers 35 can be stretchedtogether with the second web 42 with a stretchability higher than in thecase of the continuous fibers containing no lubricant even when thesefibers 35 remain in a relatively large diameter as they have beendischarged from the first extruder 31 or these fibers 35 are stretchedimmediately after discharged to a relatively small diameter.

In the second composite web 43B obtained by stretching the firstcomposite web 43A, the first continuous fibers 35 have their diameterreduced and their length increased as these continuous fibers 35 arestretched. As a result, the first web 41 has its apparent bulkinessincreased and its touch softened. In addition, the lubricant added tothe thermoplastic synthetic resin increases a fluidity of this resin andallows a nozzle temperature of the first extruder, i.e., a resintemperature to be adjusted at a level lower than in the case of thethermoplastic synthetic resin containing no lubricant. The lower theresin temperature, the easier cooling of the resin, so that the processof FIG. 4 can have a surplus resin cooling capacity and correspondinglyincrease an amount of the resin discharged from the extruder per unittime. In this way, a productivity of the first continuous fibers 35 perunit time can be increased.

The steps of the process according to this invention illustrated in FIG.4 can be modified in various manners. For example, it is possible tofeed the second web 42 onto the belt 30 before the first web 41. It isalso possible to bond the first and second webs 41, 42 together usingneedle punching or high pressure columnar water stream injectingtechnique instead of using the embossing rolls 34 or 38. Furthermore, analternative arrangement is also possible such that there is provided athird extruder at the downstream of the second extruder 32 so that thirdweb similar to the first web may be formed by inelastic third melt blowncontinuous fibers discharged from this third extruder on the second weband thereby a three-layered composite sheet 1A˜1C comprising the firstand second webs 41, 42 and the third web may be formed. The first web 41and the third web may be identical to each other or different from eachother in various factors such as type, color and fiber diameter of theresin.

FIG. 5 is a diagram similar to FIG. 4 schematically illustrating aprocess arranged in different manner from that illustrated in FIG. 4. Inthis alternative embodiment of the process, a film 52 made ofthermoplastic elastomer and being elastically stretchable in the runningdirection of the belt 30 is fed as the second web 42 from the left asviewed in the FIG. 5 and the first web 41 comprising the firstcontinuous fibers 35 is fed onto this film 52. Similarly to the case ofFIG. 4, the first and second webs 41, 42 pass through the nip definedbetween the pair of embossing rolls 34 in which they are intermittentlyfused together in the first bond regions 4A to form the first compositeweb 3A which is then stretched by the first and second rolls 36, 37.Thereafter the first composite web 3A is left to contract and, ifdesired, guided through the nip defined between the third pair of rolls38 for intermittent fusion in the second bond regions 4B to form thethird composite web 43C. By fusing the first web 41 with the second web42 in the form of the film 52 in this manner to form the first andsecond bond regions 4A, 4B, it is not apprehended that the first web 41and the second web 42 might be easily separated from each other even ifan area of the individual first and second bond regions 4A, 4B isdimensioned to be as small as in the order of 0.1˜1 mm, since the firstweb 41 comprises the continuous fibers. It should be understood,however, that the area of the first and second bond regions 4A, 4B maybe dimensioned to be as large as in the order of 10 mm².

It is possible without departing from the scope of this invention tomake the melt blown continuous fibers using ordinary melt extrudersusually used to make a spun bond nonwoven fabric or the like, instead ofthe first and second extruders 31, 32.

The first composite sheet 1A obtained by this invention is easilystretched and the second and third composite sheets 1B, 1C obtained fromthis first composite sheet 1A presents a comfortable touch. In view ofsuch characteristics, these composite sheets 1A˜1C are suitable as acloth or an elastic member used for a sanitary article such as adisposable diaper, a sanitary napkin, a disposable pants or a disposablegown used in medical site.

EXAMPLE

A stretchable web having a construction as set forth in Table 1 wasplaced upon both surfaces of elastically stretchable web having aconstruction also as set forth in Table 1, then these webs placed uponeach other were guided through a nip defined between a pair ofheat-embossing rolls. Thereby these webs were fused together in aplurality of bond regions occupying 15% of a total web surface area toobtain an elastically stretchable first composite sheet corresponding tothat according to this invention as shown in FIG. 1. The first compositesheet was stretched by 150% in one direction, then left to contract andfinally cut into an appropriate dimension to obtain an elasticallystretchable second composite sheet corresponding to that according tothis invention as shown in FIG. 2. This second composite sheet exhibitedproperties as set forth in Table 1.

Control

A stretchable web was placed upon both surfaces of the elasticallystretchable web used in EXAMPLE and these webs were fused together inthe same manner as in EXAMPLE as these webs were guided through the nipdefined between the pair of embossing rolls. Thereafter these webs fusedtogether were stretched by 100% in the case of CONTROL 1 and by 150% inthe case of CONTROL 2 to obtain composite sheets. These composite sheetsobtained in the respective CONTROLs exhibited properties as set forth inTable 1.

EXAMPLE CONTROL 1 CONTROL 2 Elastic web Fiber Melt blown fiber of (Sameas EXAMPLE) (Same as EXAMPLE) ethylene-based elastomer (Note 1) Basisweight 30 g/m² Stretch 700% Fiber-diameter 200 □m Stretchable web FiberMelt blown fiber of Melt blown fiber of Melt blown fiber ofpolypropylene homo- polypropylene homo- polypropylene homo- polymer(Note 2) polymer (Note 2) polymer (Note 2) Lubricant (Note 3)  1%  0% 0% Basis weight 15 g/m² 15 g/m² 15 g/m² Fiber-diameter 12 □m 12 □m 20□m Breaking extension 300% 150% 300% Extrusion Temp. 250 □ 280 □ 280 □2^(nd) composite sheet Composite sheet from Composite sheet fromComposite sheet from the above webs the above webs the above websStretch ratio 150% 100% 150% to 1^(st) composite sheet Fiber-diameter 10□m 11 □m 18 □m Max stretch (Note 80% 30% 80% 4)

(Note 1) MI=70 g/min as measured according to JIS (Japanese IndustrialStandards) K6758

(Note 2) MI=65 g/min as measured according to JIS K6758

(Note 3) calcium stearate

(Note 4) The maximum stretchability of the composite sheet onstress-strain curve under a substantially uniform force when thecomposite sheet is stretched again in the same direction as that inwhich the composite sheet has previously been stretched.

Referring to Table 1, the fiber of CONTROL 1 made of polypropylenehomopolymer fiber and containing no lubricant has a breaking extensionlower than a breaking extension presented by the fiber of EXAMPLE madeof the same homopolymer but containing no lubricant. The composite sheetof CONTROL 1 using such fiber presents a stretchability lower than thatpresented by the second composite sheet of EXAMPLE. The fiber of CONTROL2 made of homopolymer and containing no lubricant may be thickened to adiameter of 20 □m to obtain a breaking extension substantially equal tothat presented by the fiber of EXAMPLE. The composite sheet of CONTROL 2using such thickened fiber can obtain a stretchability substantiallyequal to that presented by the second composite sheet of EXAMPLE.However, the individual fiber in the composite sheet of CONTROL 2 has adiameter as thick as 18 □m and is unable to offer a desired flexibility.

What is claimed is:
 1. An elastically stretchable composite sheetcomprising: an elastic layer that is elastically stretchable in at leastone direction; and an inelastic layer that is inelastically stretchablein said one direction and bonded to least one surface of said elasticlayer, said inelastic layer comprising at least 80% by weight ofthermoplastic synthetic fibers which contain about 0.1 to 5.0% by weightof a lubricant.
 2. The composite sheet according to claim 1, whereinsaid thermoplastic synthetic fibers comprise at least one ofpolypropylene homopolymers, ethylene/propylene copolymers, andethylene/propylene/butene copolymers.
 3. The composite sheet accordingto claim 1, wherein said elastic layer and said inelastic layer arefused together in bond regions intermittently arranged in said onedirection and a length of said thermoplastic fibers extending betweenpairs of adjacent bond regions in said one direction is longer than arectilinear distance between said pairs of adjacent bond regions.
 4. Thecomposite sheet according to claim 1, wherein said lubricant comprisesat least one of a fatty acid amide, a fatty acid ester and a metallicsoap.